The extinct mastodon continues to have an impact on modern ecosystems in South America. Although this prehistoric ancestor of the elephant species went extinct around 11,000 years ago, the large fruit plants that relied on them for seed dispersal are still around, albeit critically endangered.
A new study published in Nature Ecology & Evolution highlights how Notiomastodon platensis, a South American mastodon, was a frugivore and an essential seed spreader. These findings could also provide the missing evidence to back up a decades-old hypothesis.
“We found starch residues and plant tissues typical of fleshy fruits, such as those of the Chilean palm (Jubaea chilensis),” said Florent Rivals, ICREA research professor at IPHES-CERCA and an expert in paleodiet, in a press release. “This directly confirms that these animals frequently consumed fruit and played a role in forest regeneration.”
Essential, but Extinct Mastodons
Back in 1982, paleontologist Paul Martin and biologist Daniel Janzen proposed the “neotropical anachronisms hypothesis,” a theory that claims that some tropical plants grew large and colorful fruits to attract larger animals, like the mastodon, so that these animals could help with seed dispersal.
This idea has remained only a theory until the evidence found in the recent study. For this new research, an international team, led by Erwin González-Guarda, analyzed 96 fossilized teeth collected from the over 900-mile stretch from Los Vilos to Chiloé Island in southern Chile. Most of the fossils came from the notable Lake Tagua Tagua site.
The team pieced together a better understanding of the mastodon through isotopic analysis, fossil calculus analysis, and microscopic dental wear studies on the teeth.
“Dental chemistry gives us a direct window into the past,” said Carlos Tornero, a stable isotopes and paleoenvironmental reconstruction expert, in a press release. “By combining different lines of evidence, we’ve been able to robustly confirm their frugivory and the key role they played in these ecosystems.”
Read More: Prehistoric Animal Migration: First Evidence Found from Mastodon Tusk
Ancient Impact on Modern-Day Ecosystem
The loss of mastodons greatly reduced seed dispersal for several of these fruit-bearing species. To understand the significant impact mastodons had on their ecosystem, the research team employed a machine learning model to analyze the current status of megafauna-dependent flora in various regions across South America.
The results indicated that 40 percent of these species are now endangered, which is four times higher than in regions where monkeys and tapirs can act as seed dispersers.
“Where that ecological relationship between plants and animals has been entirely severed, the consequences remain visible even thousands of years later,” said study co-author Andrea P. Loayza in a press release.
Some of the affected species include the Chilean palm, gomortega (Gomortega keule), and the monkey puzzle tree (Araucaria araucana). These surviving species only exist in small areas around South America and have low genetic diversity. According to the study, they are the living remnants of the seeds spread by mastodons and other megafauna of that time.
“Paleontology isn’t just about telling old stories,” said Rivals in a press release. “It helps us recognize what we’ve lost — and what we still have a chance to save.”
Read More: Accidental Paleontologists Discover Mastodon Jaw in Backyard Garden
Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
Nature Ecology & Evolution. Fossil evidence of proboscidean frugivory and its lasting impact on South American ecosystems
A graduate of UW-Whitewater, Monica Cull wrote for several organizations, including one that focused on bees and the natural world, before coming to Discover Magazine. Her current work also appears on her travel blog and Common State Magazine. Her love of science came from watching PBS shows as a kid with her mom and spending too much time binging Doctor Who.
